The porous mass production process is as follows:
- recording data from the cylinder (number, weight, capacity)
- preparation of mass (mixture of water, lime, silica, carbon fibre)
- filling of the cylinder with a fluid paste of mass
- heating in the furnace under pressure; reaction between lime and silica with the formation of calcium silicates (xonolite, tobermorite)
- oven drying, with the elimination of water remaining in the porous mass
- inspection and quality control
- sand-blasting and painting of the outside surface of the cylinder
- fitting of the valve
- solvent addition subject to removal of residual air from the cylinder
- introduction of acetylene to saturation
- packaging and despatch.
SIAD AF porous mass is produced in the Osio Sopra production plant, by a dedicated division. Its production capacity is about 50 000 cylinders per year.